This project has as a primary objective the study of the relationship betweeen abnormal behavioral test results suggesting auditory dysfunction in human subjects, and the patterns of brainstem potentials obtained from these same subjects. Of particular interest are behavioral tests for which successful performance is thought to require functional integrity of the brainstem, such as masking level differences for tones and speech, and the pattern of fast brainstem potentials (0-12 msec post-stimulus onset) elicited by acoustic stimuli for the same subjects. The primary hypothesis is that particular patterns of behavioral-test abnormality are highly correlated with unique patterns of auditory brainstem potentials. The hypothesis is tested by administering a select group of auditory tests, both behavioral and electric response measures, to a group of subjects with known peripheral and central auditory nervous system disorders. These subjects are chosen from the population of the VA Wadsworth Medical Center because of the wide array of diagnosis-substantiating medical, neurologic, otologic, and radiologic data available about them. A related goal of the project is the determination of the relative power of the various behavioral and objective methods of auditory assessment in lesion identification.